My rig run with four rx550 4gb from sapphire with 1253H/s. Hole system needs about 230W, but I need to undervolt with wattman, actually I don't work really. In the next days i get two new cards for my hobby rig 🙂

I am building my first mining rig and decided to go for Monero, I found the GPU benchmark list helpful but I am wondering what is the best choice available in case I need to mine different currency in the near future. take into consideration that the cost of kw/h is 0.006 usd so it nothing and I am looking to invest around 20-30k usd.

Do I go for the 8gb or even 12gb cards, does the size of a single card matter, or I can just substitute 12gb for 2x6gb. I would like to spend the money efficiently and build up the operation slowly, I believe its better to choose a system and just duplicate it.

Depends on your goal: get a maximum hashrate with as few cards as possible, then you should go for Vega or GTX 1080Ti. If you want to get the maximum hashrate for the money invested, then cards like the RX570/580 or GTX 1060 are a better investment imho. But you then need more systems for the same hashrate of course, and each system brings additional costs for board, CPU, PSU etc.

Depends on your goal: get a maximum hashrate with as few cards as possible, then you should go for Vega or GTX 1080Ti. If you want to get the maximum hashrate for the money invested, then cards like the RX570/580 or GTX 1060 are a better investment imho. But you then need more systems for the same hashrate of course, and each system brings additional costs for board, CPU, PSU etc.

That is the issue I am trying to get the right mix and hopefully build the most efficient operation.

Electricity is out of the equation, whats i am left with is the value of the card versus the production of hashrate.

Then I would go for RX580 or GTX 1070. They have a comparable hash rate if the RX is tweaked, depending on the algo the one or the other is faster. RX580 should be cheaper though. For me (0.30 USD per kWh in Germany) power consumption matters a lot, so the RX was no option as the Pascal based cards are a lot more efficient when fixed to low voltage. My GTX 1060 only use 45-50W for monero mining while producing around 530 H/s, RX570 had over 100W and hash rate was not much better without BIOS mod.

Then I would go for RX580 or GTX 1070. They have a comparable hash rate if the RX is tweaked, depending on the algo the one or the other is faster. RX580 should be cheaper though. For me (0.30 USD per kWh in Germany) power consumption matters a lot, so the RX was no option as the Pascal based cards are a lot more efficient when fixed to low voltage. My GTX 1060 only use 45-50W for monero mining while producing around 530 H/s, RX570 had over 100W and hash rate was not much better without BIOS mod.